CN101814720B - Electric vehicle inverter apparatus and protection method therefor - Google Patents

Abstract

The invention relates to an electric vehicle inverter device and a protection method thereof. In the electric vehicle inverter device (100), when the collision detector (16) is operated by a collision between electric vehicles, the vehicle control controller (15) detects that a switch output from the collision detector (16) is turned off Signal. Then, the inverter main circuit connection switch (10) of the high-voltage battery unit (8) enters an off state. Consequently, the DC power supply from the high voltage battery (12) to the DC bus components is interrupted. In addition, the charge charged in the main circuit capacitor (7) is discharged by the forced discharge circuit part (22b).

Description

Electric vehicle inverter device and protection method thereof

Cross References to Related Applications

This application is based on and claims priority under 35 U.S.Cζ119 to Japanese Patent Application No. 2009-038271 filed on February 20, 2009.

technical field

The present invention relates to a protection circuit and method for an inverter device which is an electric vehicle semiconductor power conversion device installed in an electric car, a hybrid car, and the like.

Background technique

The electric vehicle inverter device is connected to a high voltage battery unit which integrates a high voltage interruption function and an inrush current suppression function and has a voltage of several hundred volts (V). Even when the high voltage battery unit is disconnected from the inverter device, high voltage remains in the main circuit capacitor. From the viewpoint of enhancing safety, countermeasures for preventing the occurrence of electric shocks during maintenance and in collision accidents are important. As one of the countermeasures, discharge resistors or discharge circuits have hitherto been installed in high-voltage components of inverter devices.

FIG. 11 shows a discharge circuit according to Conventional Example 1 of the motor drive apparatus disclosed in Patent Document 1. As shown in FIG.

<Operation of Discharge Circuit Disclosed in Patent Document 1>

<At the start of the motor>

As shown in FIG. 11, when the direct current (DC) brushless motor M starts (that is, the power supply circuit is in the on state), the controller 62 respectively makes the contacts of the power supply relay Ry1 into the off state (off state), and makes the The contacts of the charging relay Ry2 enter a closed state (conduction state). In addition, the controller 62 puts the contact of the normally closed relay Ry3 into an open state (off state). Under this condition, the current flowing in the discharge resistor R1 is interrupted by the contact of the normally closed relay Ry3. Therefore, charge is stored in the smoothing capacitor C through the charging resistor R2. That is, the smoothing capacitor C is charged. At this time, the charging resistor R2 is inserted between the power supply and the smoothing capacitor C. Therefore, an inrush current is prevented from flowing into the smoothing capacitor C.

"During operation of the motor"

The controller 62 brings the contacts of the power supply relay Ry1 into a closed state (conducting state) and brings the contacts of the charging relay Ry2 into an open state (off state). Therefore, the DC brushless motor M is operated at a predetermined rotation speed by the inverter 61 of the power supply circuit in a stable operation state.

"At the stop of the motor"

On the other hand, when the DC brushless motor M is stopped (ie, the power circuit is in an off state), the controller 62 brings the contact of the power relay Ry1 and the contact of the charging relay Ry2 into an open state (off state). In addition, the controller 62 brings the normally closed type relay Ry3 into a closed state (conductive state). In this state, the charge stored in the smoothing capacitor C flows through the charging resistor R1 and the normally closed relay Ry3. Therefore, the smoothing capacitor C is discharged.

FIG. 12 shows a discharge circuit according to Conventional Example 2 of a power supply device for a DC-DC converter or the like disclosed in Patent Document 2. As shown in FIG.

<Structure of Discharge Circuit Disclosed in Patent Document 2>

"Discharge current control part DL"

As shown in FIG. 12, the discharge current control section DL is constituted by a series circuit of the discharge resistor R1 and the switching element Q1. On/off control of the current path between the ground point switching element Q1 and the output terminal Out is performed by turning the switching element Q1 on and off. Therefore, ON/OFF control of the current flowing in the discharge resistor R1 can be performed.

"Charge Storage Unit CS"

The charge storage section CS is constituted by a diode D11 serving as a rectifying element and a capacitor C11 serving as a charge storage means. The anode of the diode D11 is connected to the output terminal Out, and the cathode of the diode D11 is connected to one of the electrodes of the capacitor C11 such that the other electrode of the capacitor C11 is connected to a ground point. As the charge storage part output terminal CST, the connection point between the diode D11 and the capacitor C11 is connected to the discharge control part DC. With this circuit configuration, substantially the same voltage as the output voltage can be held at the charge storage section output terminal CST which is one of the terminals of the capacitor C11. Therefore, this voltage is supplied to the discharge control part DC as the control part power supply voltage.

"Discharge Control Part DC"

A series circuit of transistor Q12, resistors R16 and R17 connected between the charge storage part output terminal CST and ground, and an input terminal for applying a bias to transistor Q12 (base electrode in this case) Resistors R18 and R19 to perform on/off control of the transistor Q12 constitute a discharge control section DC. One of the terminals of the resistor R18 is connected to the charge storage unit output terminal CST. The connection point between the resistors R18 and R19 is connected to the input terminal of the transistor Q12. The resistor R19 is connected to the input voltage detection part ID. The input detection signal output from the input voltage detection part ID is applied as an input signal to the input terminal of the transistor Q12.

"Input voltage detection part ID"

FIG. 13 is a circuit diagram showing the input voltage detecting part ID shown in FIG. 12 . As shown in FIG. 13, a series circuit of resistors R21 and R22, a series circuit of resistor R23 and Zener diode ZD21, a power supply terminal of operational amplifier AMP, and a series circuit of resistor R25 and transistor Q21 are connected at the input terminal Between In and ground. In addition, one of the terminals of the resistor R24 connected to the input terminal In at the other terminal and the output terminal of the operational amplifier AMP are connected to the input terminal of the transistor Q21. The connection point between the resistors R21 and R22 is connected to the negative input terminal of the operational amplifier AMP, and the connection point between the resistor R23 and the Zener diode ZD21 is connected to the positive input terminal of the operational amplifier AMP.

"Operation 1 of Input Voltage Detection Part ID: Output of Logic H Signal in Steady State"

In a steady state, the voltage of the input terminal In is the input voltage itself and has a logic high level. At this time, Zener diode ZD21 is turned on. The voltage at the positive input terminal of the operational amplifier AMP is the Zener voltage of the Zener diode ZD21. On the other hand, a voltage obtained by voltage division using the resistors R21 and R22 is applied to the negative input terminal of the operational amplifier AMP. This voltage is set higher than the Zener voltage. When the potential at the negative input terminal of the operational amplifier AMP is higher than the potential at the positive input terminal, the output of the operational amplifier AMP is at a logic low level. Therefore, the transistor Q21 is turned off. No current flows in resistor R25 because transistor Q21 is turned off. The input voltage detection part ID outputs a signal whose level is a logic high level as an input detection signal to the discharge control part DC. That is, in a steady state, a signal whose level is a logic high level is output from the input voltage detection part ID.

"Operation 2 of input voltage detection part ID: output of logic L signal at trailing edge time"

At the trailing time, with the voltage at the input terminal In being lowered to be equal to or lower than the Zener voltage of the Zener diode ZD21 , the potential at the positive input terminal of the operational amplifier AMP is the voltage at the input terminal In. On the other hand, the potential at the negative input terminal of the operational amplifier AMP is lower than the voltage at the input terminal In because the voltage at the input terminal In is divided by the resistors R21 and R22 . When the potential at the positive input terminal of the operational amplifier AMP is higher than the potential at the negative input terminal, the output of the operational amplifier AMP has a logic high level. Therefore, the transistor Q21 is turned on. Since the transistor Q21 is turned on, current flows in the resistor R25. The input voltage detection part ID outputs a signal whose level is a logic low level as an input detection signal to the discharge control part DC. That is, at the trailing porch timing, a signal whose level is a logic low level is output from the input voltage detection part ID.

"Operation of Discharge Circuit Disclosed in Patent Document 2"

In a steady state in which the output voltage at the output terminal Out is maintained at the rated voltage, the input voltage to the input terminal In is substantially equal to the rated voltage. Therefore, the input voltage detection part ID outputs a signal whose level is a logic high level (or an off signal (hereinafter expressed by a logic level)) as an input detection signal to a resistor which is an input terminal of the discharge control part DC R19 terminal. Since the transistor Q12 is turned off by inputting a logic high level signal to the discharge control part DC, the output of the discharge control part DC is a logic low level signal (a signal having a level equal to the ground potential, or no signal). Therefore, the input terminal of the switching element Q1 is at ground level. Therefore, switching element Q1 is turned off. No discharge current flows in discharge resistor R1. That is, in a steady state, the discharge current control part DL does not feed any discharge current.

That is, the discharge circuit according to the conventional example 2 in FIGS. 12 and 13 detects the input voltage by using the input voltage detection part ID connected to the input terminal, and outputs the input detection signal according to the input voltage to the discharge control part DC , discharge control via the discharge resistor R1 and on/off control of the switching element Q1 of the discharge current control part DL are performed based on the control part power supply voltage and the input detection signal.

Referring next to FIG. 14 , a discharge circuit according to Conventional Example 3 is shown.

"Discharging Circuit According to Conventional Example 3"

As shown in FIG. 14, the discharge circuit is constructed such that when the discharge command signal FD1 is input to the photocoupler 36 of the isolation circuit, the gate drive PNP transistor 42 is turned on, and the gate drive voltage Vc1 is passed through the resistors 43 and 41. is applied to the gate of a power metal oxide semiconductor field effect transistor (MOSFET) 40, and thus, the power MOSFET 40 is turned on, and a discharge operation is performed via a discharge resistor 39. The gate power supply circuit part 30 has a resistor 31 connected to the positive terminal P of the high voltage capacitor; a Zener diode 33 which generates the gate drive voltage Vc1 and connected to the negative terminal of the high voltage capacitor N; and an electrolytic capacitor 34 that stores charges corresponding to the voltage generated across the Zener diode 33 and supplies a gate drive power supply voltage.

"Discharging Circuit According to Conventional Example 4"

FIG. 15 shows a discharge circuit according to Conventional Example 4 in a case where an overheat protection circuit for the discharge circuit is added to the discharge circuit shown in FIG. 14 .

As shown in FIG. 15, the discharge circuit 15 is characterized in that the forced discharge circuit part 22a is provided with an overheat protection part 28 for protecting the discharge resistor 39 from overheating, so that the overheat protection part 28 is arranged at the gate resistor of the power MOSFET 40 Between the connection point of the transistor 41 and the collector of the gate drive PNP transistor 42 and the negative terminal N of the high voltage capacitor. The discharge current is detected by detecting the voltage generated across the resistor 51 . When the NPN transistor 47 is turned on by applying a voltage to the base of the NPN transistor 47 , the base of the PNP transistor 46 is connected to the voltage of 0V of the gate power supply circuit part 30 . At this time, the emitter-collector junction of PNP transistor 46 conducts to apply a base drive voltage to the base of NPN transistor 47 . Therefore, the NPN transistor 47 maintains the on state. In addition, the gate voltage of the power MOSFET 40 drops to 0V. Therefore, the power MOSFET 40 is turned on, and the discharge current is interrupted.

The operation of cutting off the gate voltage is continued in the aforementioned manner. Therefore, the discharge resistor 39 is protected from overheating by performing a discharge operation in a high voltage applied state.

[Patent Document 1] JP-A-6-276610 (page 4, and Fig. 1 )

[Patent Document 2] JP-A-2003-235241 (pages 6 to 7, and Figs. 2 and 4)

<Disadvantages of conventional discharge circuits>

However, the aforementioned high-voltage discharge circuit of the conventional electric vehicle inverter device is configured to frequently perform discharge. Therefore, the discharge resistor is large in size. The mountability of the inverter device of the vehicle deteriorates and the manufacturing cost increases due to the required space and the increase in weight.

In the case where the method of cooling the inverter device is performed by air cooling of the amplifying resistor, the cooling performance is lowered when the electric vehicle is running at a low speed. Therefore, in the worst case, the discharge resistor may go into a burnout state. Therefore, it is absolutely necessary to install the inverter device on the water cooling part of the vehicle. However, the conventional discharge circuit has a problem that the mountability to the inverter device of the vehicle becomes worse accordingly.

"Disadvantages of the Discharge Circuit According to Patent Document 1"

In the discharging circuit according to the configuration of Conventional Example 1 shown in FIG. 11 disclosed in Patent Document 1, normally closed relay Ry3 is turned on after power supply relay Ry1 and charging relay Ry2 are turned off. Therefore, the high voltage of the smoothing capacitor C is discharged through the discharge resistor R1. At this time, in the case where a conduction failure occurs in the excitation operation transistor of the charging relay Ry2 or the power supply relay Ry1 , the excitation state of the power supply relay Ry1 or Ry2 is maintained. Therefore, the high voltage power supply Vdc remains connected to the discharge resistor R1. Therefore, the discharge circuit according to Patent Document 1 has a problem of causing overheating destruction of the discharge resistor R1. The discharge circuit according to Patent Document 1 has another problem that, in the case where the power supply relay Ry1 or the charging relay Ry2 is normally off, even when the DC brushless motor M performs a regeneration operation or continues to rotate, the current continues to flow continuously. The flow in the discharge resistor R1 causes the discharge resistor R1 to overheat.

"Disadvantages of the Discharge Circuit According to Patent Document 2"

In the discharge circuit disclosed in Patent Document 2 according to the configuration according to the conventional example 2 shown in FIGS. 12 and 13 , the input voltage and the output voltage are not insulated from each other. The input side and the output side share the 0 volt line. Therefore, discharge control is performed on the output side using input voltage detection information. On the other hand, in an inverter device having a high-voltage part, the circuit control part and the detection control part are operated by a power supply circuit using a low-voltage battery, and therefore the circuit control part and the detection control part cannot be configured to have the same potential. Therefore, the inverter device provided with the high-voltage components using the discharge circuit according to Patent Document 2 has a problem that an insulating circuit must be required.

"Disadvantages of the Discharging Circuit According to Conventional Example 3"

The discharge circuit according to the configuration of Conventional Example 3 shown in FIG. 14 has the following problems. That is, there is fear of a state in which the discharge operation is not completed according to the signal state of the discharge command signal FD1 due to, for example, interruption or chattering of the low-voltage battery.

In addition, when a discharge signal is input in a high voltage application state, current continues to flow in the discharge resistor, whereby the discharge resistor overheats.

In addition, in the gate power supply circuit part 30 of the forced discharge circuit part 22 in FIG. 14, the resistance value of the resistor 31 is set to a high value because the gate power supply voltage is low. Therefore, when the inverter device is started, it takes a long time until the device reaches the gate power supply voltage capable of performing the discharge operation.

"Disadvantages of the Discharging Circuit According to Conventional Example 4"

In the discharge circuit according to the configuration of Conventional Example 4 shown in FIG. 15 , in order to prevent the occurrence of the problem of overheating of the discharge resistor 39 shown in FIG. 14 , an overheat protection circuit part 28 is added to the circuit. Although the gate drive potential can be set to 0 V and the discharge operation can be stopped when the overheat protection circuit part 28 is arranged at this mounting position, the following disadvantages may occur.

That is, since the power supply impedance of the gate power supply circuit part 30 is high, the voltage of the storage electrolytic capacitor 34 immediately drops to 0V. During this time, the gate drive PNP transistor 42 is turned off. Therefore, the amount of current flowing through the emitter-collector junction of PNP transistor 46 is zero. The base current of the NPN transistor 47 is 0, so the NPN transistor 47 is turned off, and the latch state is canceled. In the case where the terminal voltage Vpn of the main circuit capacitor 7 is kept in a high-voltage state and the discharge command signal FD1 is input, when the storage electrolytic capacitor 34 is charged to a Zener voltage close to the Zener diode 33 via the resistor 31 through the diode 38 The PNP transistor 42 is turned on again when the level of the gate supply voltage is generated. Therefore, the power MOSFET 40 is turned on. Therefore, the discharging operation is started again. A discharge current flows therefrom via the discharge resistor 38 . However, while the high voltage application state is continued, the overheated state reappears. The discharge operation and the operation of stopping the discharge for overheat protection are intermittently repeated. Therefore, there is a fear that the discharge resistor 39 will eventually reach an overheated state and a burned out state.

Contents of the invention

The present invention has been accomplished in view of this problem. An object of the present invention is to provide an inverter device which can prevent electric shock or the like from occurring at the time of maintenance, especially in an electric vehicle collision accident, and which has high reliability and is small in size and weight and The installability of the vehicle is good and the economical benefit is good, and the object of the present invention is also to provide a protection method.

In order to solve the problems, the present invention is implemented by the following configurations and methods.

According to a first aspect of the present invention, there is provided an electric vehicle inverter device comprising:

an inverter component configured to drive an alternating current (AC) electric motor mechanically connected to a vehicle drive component of the electric vehicle;

a converter part configured to convert electric power generated by an AC generator that generates electric power by an engine driving force of the electric vehicle into a DC voltage within a predetermined voltage range;

an inverter controller configured to control the inverter component and the converter component;

a main circuit capacitor connected between positive and negative lines of a DC bus (hereinafter referred to as DC bus) of the inverter and the converter; and

a forced discharge circuit part configured to discharge the charge charged in the main circuit capacitor in response to a discharge command signal,

DC power for the inverter part is supplied from a high-voltage battery unit comprising an inverter main circuit connection switch, a high-voltage battery, and an inrush current suppression circuit configured to suppressing inrush current from a high voltage battery and connected to a DC bus when the inverter main circuit connection switch is turned on,

providing control power from a low voltage battery unit comprising a low voltage battery and a switch configured to open and close the low voltage battery,

An electric vehicle inverter device receives a control signal from a vehicle control controller and a control signal from a crash detector and controls the electric vehicle inverter device in accordance with the above signals, the vehicle control controller being configured to supervise An electric vehicle is controlled, and the collision detector is connected between the vehicle control controller and the low-voltage battery and includes a switch configured to enter off when an impact due to a collision of the electric vehicle is detected. open state, where

The vehicle control controller detects an off signal indicating that a switch of the collision detector is turned off when the collision detector is operated by a collision of the electric vehicle;

The vehicle control controller puts the inverter main circuit connection switch of the high voltage battery unit into an off state, interrupts the supply of DC power to the high voltage battery of the DC bus section and outputs a discharge command signal to the forced discharge circuit components; and

The forced discharge circuit part discharges the charge charged in the main circuit capacitor.

According to a second aspect of the present invention there is provided an electric vehicle inverter device as in the first aspect, wherein

The forced discharge circuit components include:

a discharge circuit part including a discharge resistor, a power semiconductor element, and a discharge current detection resistor connected in series between the DC buses;

a discharge resistor overheat protection circuit part configured to operate by receiving, as an input thereto, a voltage generated by a voltage drop due to a discharge current flowing through the discharge current detection resistor ;

a gate power circuit part configured to generate drive power for the power semiconductor elements from a DC voltage between the DC buses;

a driving circuit part configured to give a driving signal to a control terminal of the power semiconductor element; and

a discharge signal latch circuit part configured to receive a discharge command signal according to a detection signal from the collision detector and to give a drive signal to the drive circuit part;

When receiving a discharge command signal based on a detection signal from the collision detector, the discharge signal latch circuit part maintains the conduction signal to the drive circuit part so that the discharge circuit part can continue to maintain the discharge operation conduction status; and

When the terminal voltage of the main circuit capacitor is lowered to a value close to 0 volts by a discharging operation, and when the power supply voltage of the gate power supply circuit part is lowered to be equal to or lower than the operable voltage value, the discharge operation conduction state is canceled.

According to a third aspect of the present invention, there is provided an electric vehicle inverter device as in the first aspect, wherein

The forced discharge circuit components include:

a DC-DC converter configured to convert a battery voltage supplied from the low-voltage battery into an operating voltage of a control circuit component;

a storage unit configured to store an output voltage of the DC-DC converter;

a discharge operation command input part configured to input a detection signal from the collision detector and a discharge signal from the vehicle control controller;

a discharge command delay part configured to prevent occurrence of skipping of a signal input to the discharge operation command input part;

a discharge signal isolation part configured to electrically insulate an output signal from the discharge command delay part; and

The storage part has a sufficient storage capacity to slightly delay a voltage drop due to an interruption of voltage supplied from the low-voltage battery unit at the time of a collision of the electric vehicle, and to maintain a power supply voltage at which the control circuit part is operable until A discharge operation of the forced discharge circuit part is started.

According to a fourth aspect of the present invention, there is provided an electric vehicle inverter device as in the second aspect, wherein

The gate power supply circuit part includes a resistor and a Zener diode connected in series between DC buses via a diode, and electrolytic capacitors connected in series with each other and in parallel to the resistor and the Zener diode, respectively. ;and

A Zener voltage of the Zener diode is higher than an operable voltage of the driving circuit part and equal to and lower than an allowable gate voltage of the power semiconductor element.

According to a fifth aspect of the present invention, there is provided an electric vehicle inverter device as in the second aspect, wherein

The power semiconductor elements of the discharge circuit part include MOSFETs or IGBTs.

According to a sixth aspect of the present invention, there is provided an electric vehicle inverter device as in the second aspect, wherein

The drive circuit components include:

a first gate resistor connected to the gate of the power semiconductor element comprising a MOSFET or an IGBT;

a first PNP transistor and a second gate resistor connected in series to the first gate resistor; and

a third resistor and a Zener diode connected in series to the base of the first PNP transistor;

the discharge signal latch circuit part is provided on the anode side of the zener diode; and

The discharge signal latch circuit part includes an NPN transistor and a PNP transistor connected together as a thyristor.

According to a seventh aspect of the present invention, there is provided an electric vehicle inverter device as in the second aspect, wherein

The discharge resistor overheat protection circuit part introduces the terminal voltage of the discharge current detection resistor of the discharge circuit part into the base of the NPN transistor via a resistor;

a capacitor and a resistor are connected in parallel with each other between the base-emitter junction of the NPN transistor;

the base of the PNP transistor is connected to the collector of the NPN transistor;

the collector of the PNP transistor is connected to the base of the NPN transistor; and

The emitter of the PNP transistor is connected to a connection point between the second gate resistor of the driving circuit part and the emitter of the first PNP transistor.

According to an eighth aspect of the present invention, there is provided the electric vehicle inverter device of the third aspect, wherein

The forced discharge circuit part is configured such that a discharge command latch part is provided between the discharge command delay part and the discharge signal isolation part and holds a discharge command signal; and

The forced discharge circuit part outputs a discharge state monitoring signal to a vehicle control controller.

According to a ninth aspect of the present invention, there is provided the electric vehicle inverter device as in the sixth aspect, wherein

The discharge signal latch circuit part is configured such that the emitter of a single PNP transistor is connected to the anode of the Zener diode of the drive circuit part;

The discharge signal latching circuit part does not have the function of latching the power storage command signal; and

The discharge signal latch circuit part is configured to receive a pre-latched discharge command signal and cause the drive circuit part to operate.

According to a tenth aspect of the present invention, there is provided the electric vehicle inverter device of the fourth aspect, wherein

The gate power supply circuit part is configured such that a discharge restart transistor and a discharge restart resistor connected in series to each other are connected in parallel to the Zener diode and an electrolytic capacitor connected in parallel to each other; and

When receiving a discharge restart signal from a restart command part of the vehicle control controller upon completion of a discharge operation, the gate power supply circuit part turns on the discharge restart transistor and discharge is charged in the electrolytic capacitor charge.

According to an eleventh aspect of the present invention, there is provided the electric vehicle inverter device as in the second aspect, wherein

The power semiconductor elements of the discharge circuit part are replaced by discharge relays;

exciting the field winding of the discharge relay through the drive circuit part;

one of the contacts of the discharge relay is connected to the discharge resistor; and

The other contact of the discharge relay is connected to the discharge current sense resistor.

According to a twelfth aspect of the present invention, a protection method for an electric vehicle inverter device is provided,

The electric vehicle inverter device includes:

an inverter component configured to drive an AC electric motor mechanically connected to a vehicle drive component of the electric vehicle;

a converter part configured to convert electric power generated by an AC generator generating electric power by an engine driving force of the electric vehicle into a direct current voltage within a predetermined voltage range;

an inverter controller configured to control the inverter component and the converter component;

a main circuit capacitor connected between the inverter and the DC bus of the converter; and

a forced discharge circuit part configured to discharge the charge charged in the main circuit capacitor in response to a discharge command signal,

DC power for the inverter part is supplied from a high-voltage battery unit comprising an inverter main circuit connection switch, a high-voltage battery, and an inrush current suppression circuit configured to suppressing inrush current from a high voltage battery and connected to a DC bus when the inverter main circuit connection switch is turned on,

providing control power from a low voltage battery unit comprising a low voltage battery and a switch configured to open and close the low voltage battery,

The electric vehicle inverter device receives a control signal from a vehicle control controller and a control signal from a collision detector and controls the electric vehicle inverter device according to the above signals, and the vehicle control controller is configured to an electric vehicle is supervisedly controlled, and the crash detector is connected between the vehicle control controller and the low voltage battery and includes a switch configured to when an impact due to a collision of the electric vehicle is detected into the disconnected state,

The protection methods include:

detecting, by the vehicle control controller, an off signal indicating that a switch of the collision detector is turned off when the collision detector is operated by a collision of the electric vehicle;

bringing the inverter main circuit connection switch of the high voltage battery unit into an off state by the vehicle control controller,

interrupting the supply of DC power to the high voltage battery of the DC bus component by the vehicle control controller,

outputting a discharge command signal to the forced discharge circuit part through the vehicle control controller; and

The charge charged in the main circuit capacitor is discharged by the forced discharge circuit part.

According to the thirteenth aspect of the present invention, there is provided the protection method for the inverter device of the electric vehicle according to the twelfth aspect, wherein,

The forced discharge circuit components include:

a discharge circuit part including a discharge resistor, a power semiconductor element, and a discharge current detection resistor connected in series between the DC buses;

a discharge resistor overheat protection circuit part configured to operate by receiving, as an input thereto, a voltage generated by a voltage drop due to a discharge current flowing through the discharge current detection resistor ;

a gate power circuit part configured to generate drive power for the power semiconductor elements from a DC voltage between the DC buses;

a driving circuit part configured to give a driving signal to a control terminal of the power semiconductor element; and

a discharge signal latch circuit part configured to receive a discharge command signal according to a detection signal from the collision detector and to give a drive signal to the drive circuit part;

When receiving a discharge command signal based on a detection signal from the collision detector, the discharge signal latch circuit part maintains the conduction signal to the drive circuit part so that the discharge circuit part can continue to maintain the discharge operation conduction status; and

When the terminal voltage of the main circuit capacitor is lowered to a value close to 0 volts by a discharging operation, and when the power supply voltage of the gate power supply circuit part is lowered to be equal to or lower than the operable voltage value, the discharge operation conduction state is canceled.

According to the fourteenth aspect of the present invention, there is provided the protection method for the inverter device of the electric vehicle as in the twelfth aspect, wherein

The forced discharge circuit components include:

a DC-DC converter configured to convert a battery voltage supplied from the low-voltage battery into an operating voltage of a control circuit component;

a storage unit configured to store an output voltage of the DC-DC converter;

a discharge operation command input part configured to input a detection signal from the collision detector and a discharge signal from the vehicle control controller;

a discharge command delay part configured to prevent occurrence of skipping of a signal input to the discharge operation command input part;

a discharge signal isolation part configured to electrically insulate an output signal from the discharge command delay part; and

The storage part has a sufficient storage capacity to slightly delay a voltage drop due to an interruption of voltage supplied from the low-voltage battery unit at the time of a collision of the electric vehicle, and to maintain a power supply voltage at which the control circuit part is operable until A discharge operation of the forced discharge circuit part is started.

According to a fifteenth aspect of the present invention, there is provided a protection method for an electric vehicle inverter device as in the thirteenth aspect, wherein

The gate power supply circuit part includes a resistor and a Zener diode connected in series between DC buses via a diode, and electrolytic capacitors connected in series with each other and in parallel to the resistor and the Zener diode, respectively. ;and

A Zener voltage of the Zener diode is higher than an operable voltage of the driving circuit part and equal to and lower than an allowable gate voltage of the power semiconductor element.

According to a sixteenth aspect of the present invention, there is provided a protection method for an electric vehicle inverter device as in the fourteenth aspect, wherein

The forced discharge circuit part is configured such that a discharge command latch part is provided between the discharge command delay part and the discharge signal isolation part and holds a discharge command signal; and

The forced discharge circuit part outputs a discharge state monitoring signal to a vehicle control controller.

According to a seventeenth aspect of the present invention, there is provided the protection method for an electric vehicle inverter device as in the fifteenth aspect, wherein

The gate power supply circuit part is configured such that a discharge restart transistor and a discharge restart resistor connected in series to each other are connected in parallel to the Zener diode and an electrolytic capacitor connected in parallel to each other; and

When receiving a discharge restart signal from a restart command part of the vehicle control controller upon completion of a discharge operation, the gate power supply circuit part turns on the discharge restart transistor and discharge is charged in the electrolytic capacitor charge.

<Advantages of the first and twelfth aspects of the present invention>

According to the first and twelfth aspects of the present invention, when a collision accident or the like of the electric vehicle occurs, the inverter main circuit connection switch of the high voltage battery unit is released immediately based on the collision detection signal output from the collision detector. At the same time, the collision detection signal is input as a discharge command signal to the forced discharge circuit part of the inverter device. Then, the high voltage generated on the charged main circuit capacitor is discharged through the discharge resistor. Accordingly, the present invention has the advantage of being able to prevent overheating of a high voltage battery caused by a short circuit current due to a damaged power line or contact of a vehicle body with a high voltage component and to provide an electric vehicle inverter device with improved safety.

<Advantages of the Second and Thirteenth Aspects of the Invention>

According to the second and thirteenth aspects of the present invention, the discharge command signal generated when the collision of the vehicle occurs is latched by the discharge signal latch circuit part. Therefore, even when the power supply from the low voltage battery to the inverter device is interrupted so that the discharge command signal cannot be used, the operating power of the forced discharge circuit part is generated from the high voltage supplied from the main circuit capacitor. Therefore, the device can continue to perform the discharge operation until the terminal voltage of the main circuit capacitor is lowered to a low voltage.

<Advantages of the Third and Fourteenth Aspects of the Invention>

According to the third and fourteenth aspects of the present invention, it is possible to prevent the skipping of the discharge command signal from occurring. Even when a low-voltage battery is interrupted, it is possible to prevent a voltage drop for a period of time. Therefore, it is possible to start the discharge operation of the forced discharge circuit part.

<Advantages of the Fourth and Fifteenth Aspects of the Invention>

According to the fourth and fifteenth aspects of the present invention, a start-up improving electrolytic capacitor is provided in the gate power supply circuit part of the forced discharge circuit part. Therefore, the gate power supply voltage can be stored therein at once. Therefore, even when a discharge command signal is input simultaneously with the activation of the device, a discharge operation can be performed.

<Advantages of the fifth aspect of the present invention>

According to the fifth aspect of the present invention, various types of power semiconductor elements such as MOSFETs or insulated gate bipolar transistors (IGBTs) can be utilized. In particular, when a gate drive type power semiconductor element is used, gate current is consumed only when the gate drive type power semiconductor element is turned on. Therefore, gate drive power can be minimized. Design flexibility can be enhanced.

<Advantages of the sixth aspect of the present invention>

According to the sixth aspect of the present invention, the power storage command signal is latched by the discharge signal latch circuit part. Therefore, even when the power supply from the low-voltage battery to the inverter device is interrupted so that the discharge command signal is "down", the device can continue to apply the gate voltage to the power semiconductor elements of the discharge circuit part. Therefore, the device can maintain the discharge operation until the output voltage of the gate power supply circuit part is lowered to a value equal to or lower than the predetermined voltage.

<Advantages of the seventh aspect of the present invention>

According to the seventh aspect of the present invention, even in the case where the discharge resistor reaches an overheating condition while the inverter device maintains a state in which a high voltage is applied to its main circuit capacitor, the device performs power cutoff of the discharge circuit part according to the discharge current detection signal. MOSFET gate voltage operation. Therefore, the device stops the discharge operation. In addition, even when there is no discharge current detection signal, overheating of the discharge resistor can be prevented by maintaining the discharge operation stop state while continuing to apply high voltage to the main circuit capacitor.

<Advantages of the Eighth, Ninth and Sixteenth Aspects of the Present Invention>

According to the eighth, ninth and sixteenth aspects of the present invention, no discharge signal latch circuit part is provided in the high voltage terminal side forced discharge circuit part, and the discharge signal latch circuit part is provided on the low voltage terminal side. In addition, the discharge command latch signal is output to the vehicle control controller as a discharge state signal. Then, the discharge operation is monitored. Therefore, overheating of the discharge resistor can be prevented by controlling the high voltage so as not to be applied to the inverter device during the discharge operation.

Power from the low voltage battery is interrupted by the operation of the crash detector. Therefore, the control supply voltage is maintained for a period of time by the storage means. However, when the control power supply voltage is lowered to a value close to 0V, the discharge command latch signal is automatically canceled. Therefore, the discharging operation can be stopped.

<Advantages of the Tenth and Seventeenth Aspects of the Invention>

According to the tenth and seventeenth aspects of the invention, the discharge restart signal is output from the restart command section of the vehicle control controller to the discharge restart transistor of the forced discharge circuit section. Therefore, the output voltage of the gate power supply circuit part is lowered to 0V. Therefore, even when a high voltage is applied again to the forced discharge circuit part upon completion of the discharge operation, the restart operation can be performed in a short time.

<Advantages of the eleventh aspect of the present invention>

According to the eleventh aspect of the present invention, the relay can be used as a substitute for the power semiconductor element of the discharge circuit part. When noise or the like damages the gate member, a malfunction may occur in the power semiconductor element so that the circuit enters a constant conduction state. On the other hand, the relay has a structure in which the field winding and the contact point parts are insulated from each other so that the relay resists the influence of noise. Therefore, there is no concern that the circuit may enter a failure mode that a circuit in which a power semiconductor element is used may enter.

Description of drawings

Embodiments of the present invention will be described in detail based on the following drawings, in which:

1 is a diagram showing the overall configuration of an electric vehicle inverter device and peripheral devices according to Embodiment 1 of the present invention;

FIG. 2 is a diagram showing details of a forced discharge circuit part 22b according to Embodiment 2 of the present invention;

3A to 3C are waveform diagrams showing a discharge operation of the forced discharge circuit part 22b according to Embodiment 2 of the present invention;

4 is a diagram showing a start-up current path to the gate power supply circuit part 30a of the forced discharge circuit part 22b according to Embodiment 2 of the present invention;

5A to 5D are waveform diagrams showing rise characteristics of the output voltage of the power supply circuit part 30a in the presence of the start-up improving electrolytic capacitor 32 shown in FIG. 4 and in the absence of the start-up improving electrolytic capacitor 32;

6 is a diagram showing the operation of protecting the discharge resistor 39 of the forced discharge circuit part 22b according to Embodiment 2 of the present invention from overheating;

7A to 7E are waveform diagrams illustrating the operation of the discharge resistor overheating protection circuit part 28a in FIG. 6, which respectively show waveforms of signals at components of the circuit part 28a;

FIG. 8 is a diagram showing details of a forced discharge circuit part 22c according to Embodiment 3 of the present invention;

FIG. 9 is a diagram showing details of a forced discharge circuit part 22d according to Embodiment 4 of the present invention;

FIG. 10 is a diagram showing details of a forced discharge circuit part 22e according to Embodiment 5 of the present invention;

11 is a diagram showing a discharge circuit in a motor drive device according to Conventional Example 1;

12 is a diagram showing a discharge circuit in a power supply circuit according to Conventional Example 2;

FIG. 13 is a circuit diagram showing the input voltage detection circuit ID shown in FIG. 12;

14 is a circuit diagram showing a discharge circuit according to Conventional Example 3 supplied with a gate power supply circuit part 30 generating a gate drive voltage from a high voltage; and

FIG. 15 is a diagram showing a discharge circuit according to Conventional Example 4 constructed by adding a discharge resistor overheat protection circuit part 28 to the discharge circuit shown in FIG. 14 .

Detailed ways

Hereinafter, embodiments of the present invention are described with reference to FIGS. 1 to 10 .

Although an actual inverter device installed in an electric vehicle integrates various functions and devices, the embodiments are described by showing only functions and devices related to the present invention in the drawings. Duplicated descriptions of devices and functions are omitted by designating the same functions or devices using the same reference numerals.

[Example 1]

FIG. 1 is a diagram showing the overall configuration of an electric vehicle inverter device and peripheral devices according to Embodiment 1 of the present invention.

<Circuit Configuration of Embodiment 1>

Referring to FIG. 1 , reference numeral 1 designates vehicle drive components such as tires and wheels. Reference numeral 2 denotes an electric vehicle power generation engine part. Reference numeral 3 designates a three-phase AC electric motor mechanically connected to the vehicle drive part 1 . Reference numeral 4 denotes a three-phase AC generator for generating electric power by the driving force of the engine. Reference numeral 100 designates an inverter device. Reference numeral 8 denotes an on-vehicle high-voltage battery unit. Reference numeral 15 designates a vehicle control controller for supervisory control of the entire vehicle. Reference numeral 16 denotes a collision detector which operates to turn off an internal switch when an impact caused by a collision between electric vehicles is detected. Reference numeral 17 designates a low-voltage battery unit.

"Structure of Inverter Device 100"

The inverter device 100 includes an inverter section 5 for driving the three-phase AC motor 3; a converter section 6 for converting electric power generated by the three-phase AC generator into a DC voltage within a predetermined voltage range; a main circuit capacitor 7 connected between the inverter part 5 and the common DC bus of the converter part 6; a voltage detector 13 used for For detecting the DC voltage of the main circuit; the inverter controller 14, the inverter controller 14 is used to control the inverter part 5 and the inverter part 6; and the forced discharge circuit part 22b, the forced discharge circuit part 22b is used The charge stored in the main circuit capacitor 7 charged to a high voltage is discharged according to a command indicated by a discharge signal 20 or 21 .

The inverter section 5 is a known three-phase inverter circuit including six IGBTs and freewheeling diodes respectively connected inversely in parallel to the IGBTs.

The converter section 6 is constituted by a circuit including six IGBTs and freewheeling diodes respectively connected to the IGBTs in antiparallel.

"Structure of Vehicle High Voltage Battery Unit 8"

Reference numeral 8 designates an on-vehicle high-voltage battery unit including a high-voltage battery inrush circuit 9 , an inverter main circuit connection switch 10 , an inrush current suppression resistor 11 , and an on-vehicle high-voltage battery 12 such as a lithium battery.

"Functions of the Vehicle Control Controller 15"

The vehicle control controller 15 controls the inverter controller 14 of the inverter device, the forced discharge circuit part 22b, the high-voltage battery unit 8, other peripheral devices, and the like. A signal 20 output from the vehicle control controller 15 represents a discharge signal ( FD1 ) synchronized with a detection signal output from the collision detector 16 . A signal 21 represents a discharge signal ( FD2 ) output from the vehicle control controller 15 .

"Structure of Low-Voltage Battery Unit 17"

The low-voltage battery unit 17 includes a low-voltage battery 18 and a switch 19 whose on/off control is performed by the vehicle control controller 15 .

Next, the operation of Embodiment 1 is described hereinafter with reference to FIG. 1 .

<Problem 1 at the time of collision: Short-circuit current of high-voltage battery 12 may be generated>

In a case where electric vehicles collide with each other due to some accident or the like, short-circuit current flows through the high-voltage battery 12 when the high-voltage component connection cables of the inverter device 100 are damaged due to impact such as vehicle body collision and contact. Therefore, there is a concern that the high-voltage battery 12 may overheat.

<Problem 2 at the time of collision: Short-circuit current of main circuit capacitor 7 may be generated>

There is a concern that contact between the damaged cable and the vehicle body may short both terminals of the main circuit capacitor 7 of the inverter device 100 and a short circuit current due to high voltage may flow.

<Operation for solving problem 1>

When the collision detector 16 detects an impact caused by a collision of the electric vehicle, an internal switch of the collision detector 16 is turned off. The collision detector 16 is connected between the low-voltage battery unit 17 and the vehicle control controller 15 . Therefore, when the switch of the collision detector 16 is turned off, the voltage from the low-voltage battery 18 is not supplied to the vehicle control controller 15 . In response to the voltage cutoff signal, the inverter main circuit connection switches 10 of the high voltage battery unit 8 are simultaneously turned off, so that the connection between the high voltage battery unit 8 and the main circuit components of the inverter device 100 is forcibly disconnected. By doing this it is possible to avoid the risk of overheating the high voltage battery 12 due to the short circuit current.

<Operation 1 for solving problem 2>

Using the discharge signal ( FD1 ) 20 operating in the OFF state, or the discharge signal ( FD2 ) 21 output from the vehicle control controller 15 , the forced discharge circuit part 22 b is made to perform a discharge operation. Therefore, the high voltage generated on the main circuit capacitor 7 of the inverter device 100 is forcibly discharged. Therefore, it is possible to prevent short-circuit current and the like from being generated due to contact of the damaged cable to the vehicle body.

<Operation 2 for solving problem 2>

When the state of the vehicle drive key of the electric vehicle is changed from the conduction device to the off state, the switch 19 of the low voltage battery unit 17 is turned off. Accordingly, the low voltage battery 18 is disconnected from the aforementioned crash detector 16 . Therefore, the apparatus can obtain advantages similar to those in the foregoing case where the collision detector 16 operates. Therefore, the high voltage generated on the main circuit capacitor 7 of the inverter device 100 can be discharged by the forced discharge circuit part 22b.

[Example 2]

<Circuit Configuration of Embodiment 2>

FIG. 2 is a diagram showing details of the forced discharge circuit part 22b shown in FIG. 1 according to Embodiment 2 of the present invention. As shown in FIG. 2 , the circuit according to Embodiment 2 includes a collision detector 16 , a vehicle control controller 15 , a forced discharge circuit part 22 b , and a main circuit capacitor 7 of an inverter device 100 . Collision detector 16 (see FIG. 1 ) connected to low-voltage battery unit 17 in the "OFF" state outputs discharge signal (FD1) 20 to forced discharge circuit part 22b via vehicle control controller 15 as a collision detection signal.

In addition, the vehicle control controller 15 connects the collector of the emitter-grounded transistor 52 to the discharge signal ( FD1 ) 20 . The vehicle control controller 15 outputs the discharge signal ( FD2 ) 21 to the forced discharge circuit part 22 b in response to the conduction operation of the emitter grounded transistor 52 . The forced discharge circuit part 22b is connected to the terminals P and N of the main circuit capacitor 7 and includes a functional block part 221 and a forced discharge circuit 222 controlled by the functional block part 221 .

First, the function block part 221 is described below with reference to FIG. 2 .

<Circuit Configuration of Functional Block Part 221 >

The functional block part 221 includes a low-voltage battery 18, a 12V-5V voltage conversion DC-DC converter 37, a +5V storage part 23, a discharge operation for receiving and inputting the aforementioned discharge signal (FD1) 20 and discharge signal (FD2) 21 A command input part 24 , a discharge command delay part 25 , and a discharge signal insulation part 26 .

Next, the forced discharge circuit 222 is described below.

<Circuit Configuration of Forced Discharge Circuit 222 >

The forced discharge circuit 222 includes a discharge signal latch circuit part 27, a discharge resistor overheating protection circuit part 28a, a PNP transistor drive circuit part 29, a gate power supply circuit part 30a, a discharge circuit part 40H, and a drive for driving the power MOSFET 40 Circuit part 40K.

1) The discharge signal latch circuit section 27 includes a PNP transistor 46a and an NPN transistor 47a connected together as a thyristor.

2) The discharge resistor overheat protection circuit part 28a includes a discharge current detection resistor 51, which is used to detect the discharge current; a delay resistor 50, which is used to delay the detected voltage; A detection voltage delay capacitor 48 therein; a resistor 49 for connecting in parallel to the capacitor 48 ; and a PNP transistor 46 and an NPN transistor 47 constituting a latch circuit.

3) The discharge circuit part 40H includes a discharge transistor 39 and a power MOSFET 40.

4) The drive circuit 40K for driving the power MOSFET 40 includes a gate drive transistor 41, which is used to drive the gate of the power MOSFET 40; a power MOSFET gate drive PNP transistor 42; and a resistor 43, the The resistor 43 is also used as a power MOSFET gate drive resistor and for reducing inrush current when the discharge resistor overheat protection circuit part 28a is driven.

5) The PNP transistor drive circuit section 29 includes a resistor 44 used for the base of the PNP transistor 42 , and a Zener diode 45 used as a reference power supply for the base of the PNP transistor 42 .

6) The gate power supply circuit part 30a includes a resistor 31 for limiting current when electric power is supplied; a Zener diode 33 for generating a gate power supply voltage; an electrolytic capacitor 34 for electrolytically The capacitor 34 serves as a storage means for storing the gate power supply voltage; and the start-up improving electrolytic capacitor 32 capable of rapidly performing supply of start-up power at start-up. The gate power supply circuit part 30a generates electric power from the high voltage generated on the main circuit capacitor 7 and supplies the electric power to the gate circuit part for the power MOSFET 40, and to the discharge resistor overheat protection circuit part 28a. A voltage that can be applied to the Zener voltage of the Zener diode 33 is equal to or higher than the Zener voltage of the Zener diode 45 and equal to or lower than the allowable gate voltage of the power MOSFET 40.

Next, the discharge operation of the forced discharge circuit 222 and the functional block part 221 of the forced discharge circuit part 22b is described hereinafter with reference to FIG. 2 .

<The operation of the discharge circuit can be performed for a period of time even when the battery cell is turned off at the time of collision>

When the impact detector 16 detects an impact, the switch 19 of the low-voltage battery unit 17 is opened. At the same time, the low-voltage battery 18 of the forced discharge circuit part 22b is disconnected. Therefore, no electrical power is provided from the low voltage battery 18 . Control power supply for circuit operation is necessary for the discharge operation command input section 24, the discharge command delay section 25, and the discharge signal insulation section 26 of the forced discharge circuit section 22b. When the power for control is not supplied thereto, the discharge operation cannot be performed. Therefore, the operation of the discharge circuit can be performed by providing the +5V storage part 23 in the forced discharge circuit part 22b, wherein the +5V storage part 23 even when the power supply for control from the low-voltage battery unit 17 (supplied from the low-voltage battery 18 power) is capable of maintaining power for control for a period of time when it is interrupted.

There is concern that a skip signal and noise may be superimposed on the discharge signal ( FD1 ) 20 serving as a disconnection signal to be used when the collision detector 16 operates. However, in order to prevent the occurrence of this failure, filtering is performed at the discharge command delay section 25 after the discharge operation command input section 24 receives the signal. Therefore, malfunction is prevented. Because the high-voltage circuit part and the low-voltage circuit part are insulated by the discharge signal insulating part 26 . Therefore, the operation of the discharge signal latch circuit part 27 of the high voltage circuit part can be performed.

<Discharging operation of the discharging circuit>

Next, the discharge operation is briefly described below.

When the collision detector 16 is operated by a collision of the electric vehicle, the discharge signal ( FD1 ) 20 is transmitted therefrom, so that the discharge signal latch circuit part 27 is turned on. Accordingly, the gate drive PNP transistor 42 is turned on. Accordingly, the gate of the power MOSFET 40 is driven, so that the power MOSFET 40 is turned on.

The terminal voltage Vpn of the main circuit capacitor 7 is short-circuited through the power MOSFET 40 via the discharge resistor 39 . Accordingly, a discharge operation is performed to set a discharge curve representing the discharge current Id, as shown in FIG. 3B . The terminal voltage Vpn is lowered to 0V as shown in FIG. 3A. Instead of using the aforementioned power MOSFET 40, an IGBT and a bipolar transistor can constitute the discharge circuit part 40H.

The gate power supply circuit part 30a is connected to the high voltage part of the main circuit. Therefore, the gate power supply circuit part 30a can supply the gate power supply voltage until the discharge is completed. Therefore, when a collision between vehicles occurs, a discharge signal ( FD1 ) 20 is sent from the collision detector 16 . After the discharge signal latch circuit part 27 is turned on, the discharge signal is maintained until the output voltage of the gate power supply circuit part 30 a is lowered to around the Zener voltage of the Zener diode 45 .

Therefore, the discharge circuit is constructed so that even in the case where no discharge signal is input for a long time after the low-voltage battery 18 is interrupted, the discharge signal and the gate power supply circuit part 30a each supplied with electric power from an independent power supply are passed through each of them. The latch circuit section 27 is capable of performing a discharge operation.

Even in the case where the discharge signal ( FD1 ) 20 is canceled midway through the discharge operation, as shown in FIG.

In the case where the terminal voltage Vpn of the main circuit capacitor 7 is equal to 0 V, when the output voltage of the gate power supply circuit part 30a for the gate of the power MOSFET 40 is reduced below the determined gate drive PNP transistor 42 by the discharge operation The discharge signal of the discharge signal latch circuit part 27 is canceled when the Zener voltage of the base reference voltage of the Zener diode 45 is reached.

<Operation of Improved Rising Characteristics of Output Voltage of Gate Power Supply Circuit Part>

Next, an operation for improving the rise characteristic of the output voltage of the gate power supply circuit part 30a at the time of startup is described.

When the electric vehicle inverter device 100 is started, the current I1 flows from the high-voltage battery unit 8 through the start-improving electrolytic capacitor 32 and the gate power supply electrolytic capacitor 34 of the gate power supply circuit part 30a. The internal terminal voltage Vc1 of the gate power supply electrolytic capacitor 34 rises to the Zener voltage of the Zener diode 33 by the charge capacitor 34 . In the case where the voltage Vc1 of the gate power supply electrolytic capacitor 34 is lowered after charging the capacitor 34, the current I1 flows from the high voltage battery unit 8, thereby maintaining the output voltage of the gate power supply circuit part 30a.

In the case where the start-improving electrolytic capacitor 32 is not provided, the current I1 flows through the path of the current I1' at start-up. Therefore, the rise time of the voltage Vc1 of the gate power supply electrolytic capacitor 34 increases, as shown in FIG. 5 . In the case where the time Ts2 taken for the voltage Vc1 of the gate power supply electrolytic capacitor 34 to reach a power supply voltage value capable of discharging operation (hereinafter referred to as “dischargeable voltage”) is too long, for example, when the electric vehicle is started immediately after When a collision between electric vehicles occurs, and when the output voltage of the gate power supply circuit part 30a does not reach the dischargeable voltage, the discharging operation is not performed although the discharging signal ( FD1 ) 20 is transmitted.

When the power supply is activated at startup, the capacity of the startup improvement electrolytic capacitor 32 is selected so that the voltage Vc1 of the gate power supply electrolytic capacitor 34 reaches a dischargeable voltage in a safe startup time Ts1. Therefore, as shown in FIG. 5B and FIG. 5C , starting the voltage Vc2 of the improved electrolytic capacitor 32 enables the output voltage of the gate power supply circuit part 30 a to rise immediately.

<Operation to protect the discharge resistor from overheating>

Next, the operation of protecting the discharge resistor 39 from overheating is described hereinafter with reference to FIG. 6 .

When the high-voltage battery cell 8 is in the OFF state, and the discharge command FD1 is input to the discharge signal latch circuit part 27, the gate drive PNP transistor 42 for driving the gate of the power MOSFET 40 is turned on. Then, a voltage is applied to the gate of the power MOSFET 40, so that the power MOSFET 40 is turned on. At this time, the discharge current Id flows through the discharge resistor 39 due to the high voltage of the main circuit capacitor 7 . The discharge current Id has a waveform shown in FIG. 3B represented by a decay curve, and decreases to 0 by flowing through a path designated by number (1).

Then, when the high-voltage battery unit 8 fails and remains connected to the main circuit of the inverter device, the current Id continues to flow in the discharge resistor 39 . Therefore, the discharge resistor 39 overheats and enters a high temperature state. Finally, the discharge resistor 39 is damaged. Under certain operating conditions of the inverter device, the high temperature continues to be applied for a long time. In such a case, when the discharge command FD1 is input, the discharge resistor 39 may be damaged at high temperature. Therefore, the discharge resistor 39 must be protected by turning off the power MOSFET 40 during the conduction time during which the discharge resistor 39 is not overheated and is not damaged.

Referring to FIG. 6, the time constant of the delay circuit including the resistor 50 and the capacitor 48 is set to a discharge allowable time Ts as shown in FIG. 7C which will be described below. When the output voltage obtained from the terminal voltage of the discharge current detection resistor 51 via the resistor 50 and the capacitor 48 through the path designated by number (2) exceeds V2, the NPN transistor is turned on through the route designated by number (3). When the NPN transistor 47 is turned on, base current flows from the emitter of the PNP transistor 46 through the path designated by number (4). Then, the emitter-collector junction of the PNP transistor 46 is turned on, so that current flows in the base of the NPN transistor 47 . At this time, a resistor 43 is installed between the gate power supply electrolytic capacitor 34 and the PNP transistor 46 . Therefore, the present embodiment has a function of suppressing the inrush current through the path designated by number (5) when the transistor is turned on, thereby preventing the transistor from being damaged.

When the high voltage continues to be applied to the main circuit capacitor 7 , current continues to flow through the path indicated by the number ( 4 ) shown in FIG. 6 via the diode 38 and the resistor 31 . The input voltage to the gate drive PNP transistor 42 remains interrupted. Therefore, the gate voltage of the power MOSFET 40 becomes 0V. As long as the high voltage continues to be applied, the power MOSFET remains off to prevent the discharge resistor 39 from overheating and being damaged.

When the high-voltage battery cell 8 is in the disconnected state, and the voltage Vpn of the main circuit capacitor 7 is 0V, and the output voltage of the gate power supply circuit part 30a is lowered to 0V, the energized state of the PNP transistor 46 and the NPN transistor 47 is canceled and becomes cut off. Therefore, the discharge stop state (protection latch state) is canceled. The device is returned to a state in which all circuits are not damaged and can be restarted.

FIGS. 7A to 7E are waveform diagrams showing the operation of the discharge resistor overheat protection circuit part 28a in FIG. 6, which respectively show waveforms of signals at components of the circuit part 28a. Hereinafter, the operation of the protection discharge resistor 39 is described by referring to FIGS. 7A to 7E .

As shown in FIG. 7A , when the inverter main circuit connection switch 10 of the high voltage battery unit 8 is in the on state, the terminal voltage Vpn of the main circuit capacitor 7 is in a high voltage state. When a discharge signal (FD1) 20 (see FIG. 6 ) is input to the formed discharge circuit part 22b in this state, the power MOSFET 40 is turned on so that a discharge current Id flows through the discharge resistor 39. However, the high voltage battery 12 (see FIG. 1 ) remains connected to the inverter main circuit. Therefore, the terminal voltage Vpn is maintained at a constant voltage, as shown by the waveform of the voltage Vpn shown in FIG. 7B. Accordingly, the discharge current Id enters a state in which the discharge current Id keeps flowing as a constant current. Therefore, there is a fear that the discharge resistor 39 may overheat and may burn out.

Therefore, the discharge resistor overheat protection circuit part 28a shown in FIG. In addition, the discharge resistor overheat protection circuit part 28a remains interrupted and turns off the power MOSFET 40 (see FIG. 7C ). When the high-voltage battery 12 remains connected to the inverter main circuit, the protection latch state of the discharge resistor overheat protection circuit part 28a is canceled. Therefore, the power MOSFET 40 remains off, so that the discharge resistor 39 is not energized and is not overheated.

Next, when the inverter main circuit connection switch 10 of the high voltage battery unit 8 is turned off, the voltage Vpn is gradually lowered as shown in FIG. 7B because the high voltage battery 12 is not connected to the inverter main circuit. When Vpn=0V, the output voltage of the gate power supply circuit part 30a is 0V. Therefore, the protection latch state of the latch circuit including the PNP transistor 46 and the NPN transistor 47 is canceled.

[Example 3]

<Difference Between Forced Discharge Circuit Part According to Embodiment 3 and Forced Discharge Circuit Part According to Embodiment 2>

FIG. 8 is a diagram showing details of a forced discharge circuit part 22c according to Embodiment 3 of the present invention.

The difference between the forced discharge circuit part 22b shown in FIG. 2 and the forced discharge circuit part 22c according to Embodiment 3 is as follows. 1) As shown in FIG. 8, a discharge command latch component is added. The discharge state signal ( FD3 ) 54 output from the discharge command latch unit 55 is connected to the emitter ground transistor 53 to monitor the discharge state of the vehicle control controller 15 . 2) The discharge signal latch circuit part 27 shown in FIG. 2 is replaced with a PNP transistor 46b. The resistor 35 and the NPN transistor 52 shown in FIG. 2 are omitted.

In the following, functional block components and their circuit configurations related to their aforementioned differences are described.

8, when the discharge signal (FD1) 20 used as a collision detection signal is input to the discharge command latch part 55 through the discharge operation command input part 24 and the discharge command delay part 25, the discharge command latch part 55 will discharge the signal It is output to the discharge signal insulating part 26 as a discharge latch signal. In addition, a discharge state signal (FD3) 54 is output. The present embodiment is configured such that the latch function of the discharge signal latch circuit section 27 shown in FIG.

Next, the operation of monitoring discharge performed by the forced discharge circuit section 22c is described hereinafter with reference to FIG. 8 .

<Discharge monitoring operation performed by forced discharge circuit part 22c>

<Start of discharge operation>

The discharge operation signal from the discharge operation command input section 24 and the discharge command delay section 25 is held by the discharge command latch section 55 (latch operation is performed). The discharge latch signal is converted into an isolation signal having a low level by the discharge signal isolation part 26 . Therefore, the PNP transistor 46b is turned on. As a result of this operation, the gate drive PNP transistor 42 for driving the gate of the power MOSFET 40 is turned on. Then, the power MOSFET 40 is turned on. Therefore, an operation of discharging the main circuit capacitor 7 is performed via the discharging resistor 39 .

《Stop of discharge operation》

Simultaneously with the latch operation of the discharge command latch section 55, the low-voltage battery 18 is disconnected. The potential of the +5V storage unit 23 is gradually lowered to 0V. Therefore, the latch state is canceled. When the latch state is removed and the discharge command signal is removed, the PNP transistor 46b is turned off to interrupt the gate voltage of the power MOSFET 40. Therefore, the discharging operation is stopped.

"Monitoring of discharge operation"

The signal latched by the discharge command latch section 55 is synchronized with the discharge operation of the forced discharge circuit section 22c. The latch signal of the discharge command latch section 55 is output to the emitter grounded transistor 53 for monitoring the discharge state of the vehicle control controller 15 as a discharge state signal ( FD3 ) 54 . Therefore, the discharge state can be monitored.

[Example 4]

FIG. 9 is a diagram showing details of a forced discharge circuit part 22d according to Embodiment 4 of the present invention.

<Difference Between Forced Discharge Current Part According to Embodiment 4 and Forced Discharge Current Part According to Embodiment 2>

The difference between the forced discharge circuit part 22d according to Embodiment 4 and the forced discharge circuit part 22b shown in FIG. 2 according to Embodiment 2 is as follows.

Referring to FIG. 9 , the collector of the discharge restart transistor 57 is connected to the high-voltage side electrode of the gate power supply electrolytic capacitor 34 . The emitter of the discharge restart transistor 57 is connected to the low voltage side electrode of the gate power supply electrolytic capacitor 34 via the discharge restart transistor 56 . The discharge restart signal 60 output from the restart command section 58 of the vehicle control controller 15 is input to the base of the discharge restart transistor 57 .

<Discharge Restart Operation of Forced Discharge Circuit Part 22d According to Embodiment 4>

Next, the discharge restart operation of the forced discharge circuit part 22d is described hereinafter with reference to FIG. 9 .

In the case where the high voltage is applied again just when the discharge operation is completed, the voltage of the electrolytic capacitor 34 of the gate power supply circuit part 30b is set equal to or higher than the Zener diode 45 which supplies the base reference voltage of the gate drive PNP transistor 42 the zener voltage. Therefore, the hold state of the discharge signal of the discharge signal latch circuit section 27 is not canceled. When a high voltage is applied to the forced discharge circuit part 22d again in this state, the discharge operation continues because the power MOSFET 40 enters the conduction state. When the discharge operation is continued while maintaining the high voltage application state, the discharge resistor overheat protection circuit part 28a operates and enters a discharge stop state (protection latch state).

When the discharge operation is completed, the voltage generated on the electrolytic capacitor 34 of the gate power supply circuit part 30b is set to 0V just before the high voltage is applied to the forced discharge circuit part 22d, the voltage generated on the electrolytic capacitor 34 is equal to or lower than Zener Zener voltage of diode 45 , which is the base voltage of PNP transistor 42 . Therefore, no current is supplied to the discharge signal latch circuit part 27 . Therefore, the discharge signal latch state is canceled. Therefore, when the high voltage is applied to the forced discharge circuit part 22d again, the discharge circuit part is not in the discharge operation state. Therefore, the discharge resistor overheat protection circuit part 28 does not operate. Perform the startup operation normally.

The discharge restart signal 60 output from the restart command section 58 of the vehicle control controller 15 upon completion of the discharge operation is input to the discharge restart transistor 57 of the forced discharge circuit section 22d. Therefore, the discharge restart transistor 57 is turned on. Then, the voltage of the gate supply electrolytic capacitor 34 is discharged and reduced to 0V through the discharge restart resistor 56 . The current supplied to the discharge signal latch circuit section 27 is eliminated by this operation. Therefore, the discharge signal latch state is canceled. Then, the discharging operation is stopped. Next, the discharge restart signal 60 is canceled therefrom. Then, high voltage is applied thereto, thereby normally performing the starting operation. Just at the completion of the discharge operation, it is possible to perform an operation of normally performing restart by applying a high voltage just at the completion of the discharge operation.

[Example 5]

<Differences between the forced discharge circuit component according to Embodiment 5 and the forced discharge circuit component according to Embodiment 4>

FIG. 10 is a diagram showing details of a forced discharge circuit part 22e according to Embodiment 5 of the present invention. The difference between the forced discharge circuit part 22e according to Embodiment 5 and the forced discharge circuit part 22d shown in FIG. 9 according to Embodiment 4 is that the power MOSFET 40 shown in FIG. 9 is replaced by a discharge relay 59. The collector of gate drive PNP transistor 42 is connected to the field winding input terminal of discharge relay 59 . The other field winding input terminal thereof is connected to a line on the terminal N side in the forced discharge circuit part 22e.

The discharge resistor 39 is connected to one of the contact parts of the discharge relay 59 . Discharge Resistor The discharge current detection resistor 51 of the overheat protection circuit part 28 a is connected to the other contact part of the discharge relay 59 .

<Operation of Forced Discharge Circuit Part 22e According to Embodiment 5>

The operation of the forced discharge circuit part 22e is described hereinafter with reference to FIG. 10 .

The gate drive PNP transistor 42 is used as a field winding drive transistor for the discharge relay 59 . The Zener voltage of the Zener diode 45 a which is the base voltage of the PNP transistor 42 is set to a voltage equal to or higher than the operating voltage of the discharge relay 59 . Even when the power MOSFET 40 (see FIG. 9) is replaced with the discharge relay 59, the discharge resistor 39 can be protected from overheating by installing the discharge resistor overheat protection circuit part 28a, similarly to the foregoing embodiment.

Similarly, the device can be started immediately by installing the gate power supply circuit part 30b. Upon completion of the discharge operation, even when the high voltage is applied to the forced discharge circuit part 22e again, the voltage of the electrolytic capacitor 34 of the gate drive circuit part 30b is set equal to or higher than the base reference of the PNP transistor 42 providing the gate drive voltage to the value of the Zener voltage of the Zener diode 45a to maintain the discharge. Therefore, the discharge signal holding state of the discharge signal latch circuit section 27 is not canceled. When the high voltage is applied to the forced discharge circuit part 22e again in this state, the discharge operation is continued because the discharge relay 59 is in the ON state. When the discharge operation is continued while maintaining the high voltage application state, the discharge resistor overheat protection circuit part 28a operates and enters a discharge stop state (protection latch state).

Upon completion of the discharge operation, the voltage of the electrolytic capacitor 34 of the gate power supply circuit part 30b is set to 0V just before the high voltage is applied again to the forced discharge circuit part 22e. Therefore, the voltage of the gate power supply circuit part 30b is equal to or lower than the voltage of the Zener diode 45a which is the base voltage of the PNP transistor 42, so that the current supplied to the discharge signal latch circuit part 27 is eliminated, and the discharge signal is latched. Status is canceled.

When the high voltage is applied to the forced discharge circuit part 22e again, the discharge resistor overheat protection circuit part 28a does not operate because the device is not in the discharge operation state. Therefore, the startup operation is normally performed.

The discharge restart signal 60 output from the restart command section 58 of the vehicle control controller 15 upon completion of the discharge operation is input to the discharge restart transistor 57 of the forced discharge circuit section 22e. Then, the discharge restart transistor 57 is turned on. Thus, the voltage of the gate supply electrolytic capacitor 34 is discharged and reduced to 0V through the discharge restart resistor 56 . The current supplied to the discharge signal latch circuit section 27 is eliminated by this operation. Then, the discharge signal latch state is canceled. The discharge operation is stopped.

Next, the discharge restart signal 60 is canceled, and a high voltage is applied. Then, perform the startup operation normally. Similar to the foregoing embodiments, a normal restart operation can be performed by applying a high voltage just when the discharge operation is completed.

The present invention is accomplished by assuming application to an inverter device installed in an electric vehicle. In particular, the inverter device according to the present invention can be applied to electric vehicles, hybrid vehicles, etc. as an inverter device having a forced discharge circuit part for preventing damage caused by high-voltage parts and damaged power lines or power lines when a collision accident occurs. Occurrence of short circuits, overheating, etc. caused by contact between metal parts.

Claims (15)

1. An electric vehicle inverter device, comprising: an inverter component configured to drive an AC electric motor mechanically connected to a vehicle drive component of the electric vehicle; a converter part configured to convert electric power generated by an AC generator generating electric power by an engine driving force of the electric vehicle into a direct current voltage within a predetermined voltage range; an inverter controller configured to control the inverter component and the converter component; a main circuit capacitor connected between the inverter and the DC bus of the converter; and a forced discharge circuit part configured to discharge the charge charged in the main circuit capacitor in response to a discharge command signal, DC power for the inverter part is supplied from a high-voltage battery unit comprising an inverter main circuit connection switch, a high-voltage battery, and an inrush current suppression circuit configured to suppressing inrush current from a high voltage battery and connected to a DC bus when the inverter main circuit connection switch is turned on, providing control power from a low voltage battery unit comprising a low voltage battery and a low voltage battery switch configured to open and close the low voltage battery, An electric vehicle inverter device receives a control signal from a vehicle control controller and a control signal from a crash detector and controls the electric vehicle inverter device in accordance with the above signals, the vehicle control controller being configured to supervise An electric vehicle is controlled, and the collision detector is connected between the vehicle control controller and the low voltage battery and includes a collision detector switch configured to detect a collision due to the electric vehicle cause the shock to go into the disconnected state, where the The vehicle control controller detects an off signal indicating that the crash detector switch is turned off when the crash detector is operated by a collision of the electric vehicle; The vehicle control controller puts the inverter main circuit connection switch of the high voltage battery unit into an off state, interrupts the supply of DC power to the high voltage battery of the DC bus section and outputs a discharge command signal to the forced discharge circuit components; and the forced discharge circuit part discharges the charge charged in the main circuit capacitor, Wherein, the forced discharge circuit components include: a discharge circuit part including a discharge resistor, a power semiconductor element, and a discharge current detection resistor connected in series between the DC buses; a discharge resistor overheat protection circuit part configured to operate by receiving, as an input thereto, a voltage generated by a voltage drop due to a discharge current flowing through the discharge current detection resistor ; a gate power circuit part configured to generate drive power for the power semiconductor elements from a DC voltage between the DC buses; a driving circuit part configured to give a driving signal to a control terminal of the power semiconductor element; and a discharge signal latch circuit part configured to receive a discharge command signal according to a detection signal from the collision detector and to give a drive signal to the drive circuit part; When receiving a discharge command signal based on a detection signal from the collision detector, the discharge signal latch circuit part maintains the conduction signal to the drive circuit part so that the discharge circuit part can continue to maintain the discharge operation conduction status; and When the terminal voltage of the main circuit capacitor is lowered to a value close to 0 volts by a discharging operation, and when the power supply voltage of the gate power supply circuit part is lowered to be equal to or lower than the operable voltage value, the discharge operation conduction state is canceled. 2. The electric vehicle inverter device according to claim 1, wherein The gate power supply circuit part includes a resistor and a Zener diode connected in series between DC buses via a diode, and electrolytic capacitors connected in series with each other and in parallel to the resistor and the Zener diode, respectively. ;and A Zener voltage of the Zener diode is higher than an operable voltage of the driving circuit part and less than or equal to an allowable gate voltage of the power semiconductor element. 3. The electric vehicle inverter device according to claim 1, wherein The power semiconductor elements of the discharge circuit part include MOSFETs or IGBTs. 4. The electric vehicle inverter device according to claim 1, wherein The drive circuit components include: a first gate resistor connected to the gate of the power semiconductor element comprising a MOSFET or an IGBT; a first PNP transistor and a second gate resistor connected in series to the first gate resistor; and a third resistor and a Zener diode connected in series to the base of the first PNP transistor; the discharge signal latch circuit part is provided on the anode side of the zener diode; and The discharge signal latch circuit part includes an NPN transistor and a PNP transistor connected together as a thyristor. 5. The electric vehicle inverter device according to claim 1, wherein The discharge resistor overheat protection circuit part introduces the terminal voltage of the discharge current detection resistor of the discharge circuit part into the base of the NPN transistor via a resistor; a capacitor and a resistor are connected in parallel with each other between the base-emitter junction of the NPN transistor; the base of the PNP transistor is connected to the collector of the NPN transistor; the collector of the PNP transistor is connected to the base of the NPN transistor; and The emitter of the PNP transistor is connected to a connection point between the second gate resistor of the driving circuit part and the emitter of the first PNP transistor. 6. The electric vehicle inverter device according to claim 4, wherein The discharge signal latch circuit part is configured such that the emitter of a single PNP transistor is connected to the anode of the Zener diode of the drive circuit part; The discharge signal latching circuit part does not have the function of latching the power storage command signal; and The discharge signal latch circuit part is configured to receive a pre-latched discharge command signal and cause the drive circuit part to operate. 7. The electric vehicle inverter device according to claim 2, wherein The gate power supply circuit part is configured such that a discharge restart transistor and a discharge restart resistor connected in series to each other are connected in parallel to the Zener diode and an electrolytic capacitor connected in parallel to each other; and When receiving a discharge restart signal from a restart command part of the vehicle control controller upon completion of a discharge operation, the gate power supply circuit part turns on the discharge restart transistor and charges the electrolytic capacitor charge is discharged. 8. The electric vehicle inverter device according to claim 1, wherein The power semiconductor elements of the discharge circuit part are replaced by discharge relays; exciting the field winding of the discharge relay through the drive circuit part; one of the contacts of the discharge relay is connected to the discharge resistor; and The other contact of the discharge relay is connected to the discharge current sense resistor. 9. An electric vehicle inverter device, comprising: an inverter component configured to drive an AC electric motor mechanically connected to a vehicle drive component of the electric vehicle; a converter part configured to convert electric power generated by an AC generator generating electric power by an engine driving force of the electric vehicle into a direct current voltage within a predetermined voltage range; an inverter controller configured to control the inverter component and the converter component; a main circuit capacitor connected between the inverter and the DC bus of the converter; and a forced discharge circuit part configured to discharge the charge charged in the main circuit capacitor in response to a discharge command signal, DC power for the inverter part is supplied from a high-voltage battery unit comprising an inverter main circuit connection switch, a high-voltage battery, and an inrush current suppression circuit configured to suppressing inrush current from a high voltage battery and connected to a DC bus when the inverter main circuit connection switch is turned on, providing control power from a low voltage battery unit comprising a low voltage battery and a low voltage battery switch configured to open and close the low voltage battery, An electric vehicle inverter device receives a control signal from a vehicle control controller and a control signal from a crash detector and controls the electric vehicle inverter device in accordance with the above signals, the vehicle control controller being configured to supervise An electric vehicle is controlled, and the collision detector is connected between the vehicle control controller and the low voltage battery and includes a collision detector switch configured to detect a collision due to the electric vehicle cause the shock to go into the disconnected state, where the The vehicle control controller detects an off signal indicating that the crash detector switch is turned off when the crash detector is operated by a collision of the electric vehicle; The vehicle control controller puts the inverter main circuit connection switch of the high voltage battery unit into an off state, interrupts the supply of DC power to the high voltage battery of the DC bus section and outputs a discharge command signal to the forced discharge circuit components; and the forced discharge circuit part discharges the charge charged in the main circuit capacitor, Wherein, the forced discharge circuit components include: a DC-DC converter configured to convert a battery voltage supplied from the low-voltage battery into an operating voltage of a control circuit component; a storage unit configured to store an output voltage of the DC-DC converter; a discharge operation command input part configured to input a detection signal from the collision detector and a discharge signal from the vehicle control controller; a discharge command delay part configured to prevent occurrence of skipping of a signal input to the discharge operation command input part; a discharge signal isolation part configured to electrically insulate an output signal from the discharge command delay part; and The storage part has a sufficient storage capacity to slightly delay a voltage drop due to an interruption of voltage supplied from the low-voltage battery unit at the time of a collision of the electric vehicle, and to maintain a power supply voltage at which the control circuit part is operable until A discharge operation of the forced discharge circuit part is started. 10. The electric vehicle inverter device according to claim 9, wherein The forced discharge circuit part is configured such that a discharge command latch part is provided between the discharge command delay part and the discharge signal isolation part and holds a discharge command signal; and The forced discharge circuit part outputs a discharge state monitoring signal to a vehicle control controller. 11. A protection method for an electric vehicle inverter device, The electric vehicle inverter device includes: an inverter component configured to drive an AC electric motor mechanically connected to a vehicle drive component of the electric vehicle; a converter part configured to convert electric power generated by an AC generator generating electric power by an engine driving force of the electric vehicle into a direct current voltage within a predetermined voltage range; an inverter controller configured to control the inverter component and the converter component; a main circuit capacitor connected between the inverter and the DC bus of the converter; and a forced discharge circuit part configured to discharge the charge charged in the main circuit capacitor in response to a discharge command signal, DC power for the inverter part is supplied from a high-voltage battery unit comprising an inverter main circuit connection switch, a high-voltage battery, and an inrush current suppression circuit configured to suppressing inrush current from a high voltage battery and connected to a DC bus when the inverter main circuit connection switch is turned on, providing control power from a low voltage battery unit comprising a low voltage battery and a low voltage battery switch configured to open and close the low voltage battery, The electric vehicle inverter device receives a control signal from a vehicle control controller and a control signal from a collision detector and controls the electric vehicle inverter device according to the above signals, and the vehicle control controller is configured to an electric vehicle is supervisedly controlled, and the crash detector is connected between the vehicle control controller and the low voltage battery and includes a crash detector switch configured to The shock caused by the collision enters the disconnected state, The protection methods include: detecting, by the vehicle control controller, an off signal indicating that the crash detector switch is turned off when the crash detector is operated by a collision of the electric vehicle; bringing the inverter main circuit connection switch of the high voltage battery unit into an off state by the vehicle control controller, interrupting the supply of DC power to the high voltage battery of the DC bus component by the vehicle control controller, outputting a discharge command signal to the forced discharge circuit part through the vehicle control controller; and discharging the charge charged in the main circuit capacitor through the forced discharge circuit part, Wherein, the forced discharge circuit components include: a discharge circuit part including a discharge resistor, a power semiconductor element, and a discharge current detection resistor connected in series between the DC buses; a discharge resistor overheat protection circuit part configured to operate by receiving, as an input thereto, a voltage generated by a voltage drop due to a discharge current flowing through the discharge current detection resistor ; a gate power circuit part configured to generate drive power for the power semiconductor elements from a DC voltage between the DC buses; a driving circuit part configured to give a driving signal to a control terminal of the power semiconductor element; and a discharge signal latch circuit part configured to receive a discharge command signal according to a detection signal from the collision detector and to give a drive signal to the drive circuit part; When receiving a discharge command signal based on a detection signal from the collision detector, the discharge signal latch circuit part maintains the conduction signal to the drive circuit part so that the discharge circuit part can continue to maintain the discharge operation conduction status; and When the terminal voltage of the main circuit capacitor is lowered to a value close to 0 volts by a discharging operation, and when the power supply voltage of the gate power supply circuit part is lowered to be equal to or lower than the operable voltage value, the discharge operation conduction state is canceled. 12. The protection method for an electric vehicle inverter device according to claim 11, wherein The gate power supply circuit part includes a resistor and a Zener diode connected in series between DC buses via a diode, and electrolytic capacitors connected in series with each other and in parallel to the resistor and the Zener diode, respectively. ;and A Zener voltage of the Zener diode is higher than an operable voltage of the driving circuit part and less than or equal to an allowable gate voltage of the power semiconductor element. 13. The protection method for an electric vehicle inverter device according to claim 12, wherein The gate power supply circuit part is configured such that a discharge restart transistor and a discharge restart resistor connected in series to each other are connected in parallel to the Zener diode and an electrolytic capacitor connected in parallel to each other; and When receiving a discharge restart signal from a restart command part of the vehicle control controller upon completion of a discharge operation, the gate power supply circuit part turns on the discharge restart transistor and charges the electrolytic capacitor charge is discharged. 14. A protection method for an electric vehicle inverter device, The electric vehicle inverter device includes: an inverter component configured to drive an AC electric motor mechanically connected to a vehicle drive component of the electric vehicle; a converter part configured to convert electric power generated by an AC generator generating electric power by an engine driving force of the electric vehicle into a direct current voltage within a predetermined voltage range; an inverter controller configured to control the inverter component and the converter component; a main circuit capacitor connected between the inverter and the DC bus of the converter; and a forced discharge circuit part configured to discharge the charge charged in the main circuit capacitor in response to a discharge command signal, DC power for the inverter part is supplied from a high-voltage battery unit comprising an inverter main circuit connection switch, a high-voltage battery, and an inrush current suppression circuit configured to suppressing inrush current from a high voltage battery and connected to a DC bus when the inverter main circuit connection switch is turned on, providing control power from a low voltage battery unit comprising a low voltage battery and a low voltage battery switch configured to open and close the low voltage battery, The electric vehicle inverter device receives a control signal from a vehicle control controller and a control signal from a collision detector and controls the electric vehicle inverter device according to the above signals, and the vehicle control controller is configured to an electric vehicle is supervisedly controlled, and the crash detector is connected between the vehicle control controller and the low voltage battery and includes a crash detector switch configured to The shock caused by the collision enters the disconnected state, The protection methods include: detecting, by the vehicle control controller, an off signal indicating that the crash detector switch is turned off when the crash detector is operated by a collision of the electric vehicle; bringing the inverter main circuit connection switch of the high voltage battery unit into an off state by the vehicle control controller, interrupting the supply of DC power to the high voltage battery of the DC bus component by the vehicle control controller, outputting a discharge command signal to the forced discharge circuit part through the vehicle control controller; and discharging the charge charged in the main circuit capacitor through the forced discharge circuit part, Wherein, the forced discharge circuit components include: a DC-DC converter configured to convert a battery voltage supplied from the low-voltage battery into an operating voltage of a control circuit component; a storage unit configured to store an output voltage of the DC-DC converter; a discharge operation command input part configured to input a detection signal from the collision detector and a discharge signal from the vehicle control controller; a discharge command delay part configured to prevent occurrence of skipping of a signal input to the discharge operation command input part; a discharge signal isolation part configured to electrically insulate an output signal from the discharge command delay part; and The storage part has a sufficient storage capacity to slightly delay a voltage drop due to an interruption of voltage supplied from the low-voltage battery unit at the time of a collision of the electric vehicle, and to maintain a power supply voltage at which the control circuit part is operable until A discharge operation of the forced discharge circuit part is started. 15. The protection method for an electric vehicle inverter device according to claim 14, wherein The forced discharge circuit part is configured such that a discharge command latch part is provided between the discharge command delay part and the discharge signal isolation part and holds a discharge command signal; and The forced discharge circuit part outputs a discharge state monitoring signal to a vehicle control controller.

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